Despite being a rival for Mayoral election next year, I’m happy to admit that Boris Johnson’s speech to his Tory chums is often the highlight of their annual conference. As an outright entertainer, few can rival the old Etonian, and Ken Livingstone has said that he feels Johnson will always be funnier than him.

But for many Londoners, Johnson’s tenure as Mayor is getting well beyond a joke.

As ever his speech was high on humour, but low on new ideas, and among those threads picked up by the media, his ruminations on river crossings were originally and rather ironically revealed on April Fool’s Day this year. These proposals are likely to put him into direct conflict with those concerned about London’s environment.

Although a cable car is a great idea, it isn’t of course his, resulting originally from a 2008 report on alternatives to the six-lane Thames Gateway Bridge, which was a 60s proposal initially supported by Livingstone but vehemently opposed by residents and defeated by a public enquiry on environmental grounds.

Johnson, who dropped the Thames Gateway plan because of local opposition, including a campaign by Green Party members, has been keen to advance the idea of a crossing at Silvertown. The aim appears to be to decrease pressure on the Blackwall Tunnel, but there has been little pretence that the idea will bring economic benefits to East London, and is principally a simple way of moving big lorries around faster, despite the horrendous health costs to Londoners young and old as a result of air pollution.

The cost is likely to be colossal, at a time when Darren Valley Hospital, right next to the Dartford Tunnel, is facing a budget deficit of £1.03 million, and will undo a significant part of any environmental benefits that have resulted from the increase in popularity in cycling.

However, perhaps the most notable element of Johnson’s speech was his failure to discuss air quality. A report delivered to Johnson in 2008 estimated that 4,000 people die prematurely in London every year as a result of poor air. This is perhaps the biggest public health problem the capital has faced since the great smog 60 years ago.

Other studies have shown the link to heart attacks, to long-term asthma and to reducing children’s lung capacity by around a fifth. Johnson published 14 policies he said were necessary to reduce air pollution to safer levels by 2015. However, in the government’s recently-published action plan, none of these policies is included despite half a dozen meetings between the Mayor’s team and Ministers.

The Deputy Mayor for Transport, Isabel Dedring, recently told the TfL Board they had “run out of ideas” for lobbying the government on air quality, but her pronouncement could act as a better synopsis for Johnson’s tenure as mayor than any of Johnson’s blithe grandiloquence and black-slapping at Tory party conference.

London needs a Mayor that can act as a leader, not a clown, and when the capital goes to the polls in May, we should remember his record, not his repertoire.